Programming Perl, 4th Edition

unshift

unshift ARRAY, LIST

This function does the opposite of shift. (Or the opposite of push, depending on how you look at it.) It prepends LIST to the front of the array and returns the new number of elements in the array:

unshift(@ARGV, "–e", $cmd) unless $ARGV[0] =~ /^–/;

Note the LIST is prepended whole, not one element at a time, so the prepended elements stay in the same order. Use reverse to do the reverse.

Starting with v5.14, unshift can take a reference to an unblessed array, which will be dereferenced automatically. This aspect of unshift is considered experimental. The exact behavior may change in a future version of Perl.